a(n) = Sum_{k=0..n} binomial(n,k) * binomial(n^2+k+1,n).
A388053
a(n) = Sum_{k=0..n} binomial(n,k) * binomial(n^2+k+1,n).
Terms
- a(0) =1a(1) =5a(2) =61a(3) =1561a(4) =63241a(5) =3522221a(6) =249612805a(7) =21462603121
External references
- oeis: A388053